65-66 Power Brake Master Cylinder without a floating piston bolt

[Dale O.]

I am rebuilding a master cylinder 65-66 pb master cylinder. I took it apart and it does not have the bolt that stops the floating piston. Has any one seen this before? Is the bolt really necessary? Should machine the cylinder and install it?

[Joe L.]

Re: 65-66 Power Brake Master Cylinder without a floating piston bolt

I am rebuilding a master cylinder 65-66 pb master cylinder. I took it apart and it does not have the bolt that stops the floating piston. Has any one seen this before? Is the bolt really necessary? Should machine the cylinder and install it?

Dale------


Master cylinder rebuilders often leave out the secondary piston stop screw. So, I expect the screw is not really necessary. I like to use them, though.

By the way, the fact that yours is missing the screw probably means it's been previously rebuilt.

[Dale O.]

Re: 65-66 Power Brake Master Cylinder without a floating piston bolt

Thanks for the response Joe. What is strange the master cylinder was never drilled or threaded for the bolt. If what your saying is true I should not worry about drilling, threading and installing the bolt.

[Guest]

Re: 65-66 Power Brake Master Cylinder without a floating piston bolt

Guys,

The screw is there for a reason. I had mine rebuilt 20 years age and never could figure out why 4 wheel disc brakes were terrible. Replaced seals a couple times and one time while reading instructions I saw location where screw was missing since rebuilder had left out. Another problem is seal kits with new pistons are not correct, not sure if they were too long or too short. Best advice when your rebuilding your master use existing piston with new seals and reinstall screw.

Rob

[Joe L.]

Re: 65-66 Power Brake Master Cylinder without a floating piston bolt

Thanks for the response Joe. What is strange the master cylinder was never drilled or threaded for the bolt. If what your saying is true I should not worry about drilling, threading and installing the bolt.

Dale------


I'm surprised that the master cylinder was never drilled and tapped for the screw. As far as I know, these stop screws were used for 1965 and later dual master cylinders. Apparently, the master cylinder worked for about 50 years without the screw so I'd say it could continue the same way. I would not attempt to drill and tap it for a screw now.

However, I agree with Rob. That's why I always install the screw. Of course, I do it on master cylinders that are already drilled and tapped for the screw.